Conventionally, paper on which an image is formed with decolorable toner is heated and subjected to decoloring processing in a decoloring apparatus to decolor the image thereon. In addition to a heat source for carrying out the decoloring processing, the decoloring apparatus also includes with a reading device which reads the image formed on the paper before the paper is subjected to the decoloring processing. The reading device may also determine whether or not the image on the paper is decolored after the decoloring processing.
However, there is a problem with such an arrangement. In a case in which the reading operation is stopped due to an error and the like before the paper which is not yet subjected to decoloring processing is read completely, part of the paper is decolored due to the relation between the length of the conveyance path and the paper position, and the paper cannot be stored correctly.